Variable stroke control device for remote hydraulic piston and cylinder assemblies



Aug. 25, 1970 w. GALLANT VARIABLE STROKE CONTROL DEVICE FOR REMOTEHYDRAULIC PISTON AND CYLINDER ASSEMBLIES Filed Aug. 26, 1968 2Sheets-Sheet 1 Q Q i UP -fll *z [8 DOWN UP ADJUST DOWN 5 44 ,5 TAM/5T IODOWN 2 NJ I4 I Q-j- UP [6.

4424/9/ 7 gem/Y7 Aug. 25, 1970 w, GALLANT 3,525,212

VARIABLE STROKE CONTROL DEVICE FOR REMOTE HYDRAULIC PISTON AND CYLINDERASSEMBLIES Flled Aug 26, 1968 Z Sheets-Sheet 2 United States Patent3,525,212 VARIABLE STROKE CONTROL DEVICE FOR REMOTE HYDRAULIC PISTON ANDCYLIN- DER ASSEMBLIES William Gallant, Roblin, Manitoba, Canada,assignor to Metered Hydraulics Ltd., Brandon, Manitoba, Canada FiledAug. 26, 1968, Ser. No. 755,079 Int. Cl. F15b 7/00, 13/04 US. Cl. 6054.59 Claims ABSTRACT OF THE DISCLOSURE My invention relates to new anduseful improvements in control devices for hydraulic piston and cylinderassemblies, particularly remotely situated hydraulic piston and cylinderassemblies as used on agricultural implements or the like.

It is conventional to provide a pump which produces hydraulic pressurein a control valve adjacent the operator which directs this pressurefluid through hoses or conduits to either front or rear of the workcylinder thus causing the plunger to move in and out thereby loweringand raising the implement components requiring control. For example, itis normal to control the depth of penetration of one-way discs, combinereels and the like.

The control valve is normally actuated manually from a pre-set neutralposition. A detent is available on some valves that hold the lever inthe up or down position until the work cylinder has completed its travelor stroke.

When the work cylinder lowers the implement component, the down stroketravel must be controlled as this regulates the depth of penetration ofthe implement component within the soil. This is usually controlled byvarious mechanical means such as blocking the down stroke that must bemanually adjusted on the work cylinder and once adjusted cannot bevaried during operation to suit conditions but rather the machine has tobe halted and the adjustment made.

A further system uses a valve built into the work cylinder that stopsthe flow of hydraulic fluid when actuated by a preset collar on theplunger. This system also must be preset before work commences andcannot be varied during use without stopping the implement.

It is generally recognized, especially with the relatively largeimplements in use today, that variable depth control is essential andthe purpose of the present invention is to provide a simple means ofpositive depth control or stroke control, operable at any time from thedriving seat of the implement or towing vehicle without the necessity ofstopping the machine to achieve this control.

I achieve this by providing a control piston and cylinder in series withone of the conduits between the pump and the work cylinder. A furtherconduit together with a further control valve is adapted to bypass thiscontrol piston and cylinder so that the position of the work piston canbe preset by this control valve whereupon same is closed and the workpiston is then actuated by the freely floating piston within the controlpiston and cylinder assembly.

3,525,212 Patented Aug. 25, 1970 A further embodiment incorporates aproportional valve in the event that the work cylinder is of arelatively large displacement compared to the control cylinder so thatonly part of the fluid flow is permitted to enter the control piston andcylinder assembly.

The principal object and essence of the invention is therefore toprovide a control piston and cylinder assembly together with a controlvalve and bypass conduit which enables the work cylinder piston to beprepositioned thus controlling the length of the down stroke thereof.

Another object of the invention is to provide a device of the characterherewithin described which can readily be fitted to existing equipmentand can include a proportioning valve in the event that the workcylinder is of a considerably larger displacement than the controlcylinder.

A yet further object of the invention is to provide a device of thecharacter herewithin described which is simple in construction,economical in manufacture, and otherwise well suited to the purpose forwhich it is designed.

With the foregoing in view, and such other objects, purposes oradvantages as may become apparent from consideration of this disclosureand specification, the present invention consists of the inventiveconcept in whatsoever way the same may be embodied having regard to theparticular exemplification or exemplifications of same herein, with dueregard in this connection being had to the accompanying figures inwhich:

FIG. 1 is a schematic view of my device shown incorporated within anhydraulic system.

FIG. 2 is an enlarged sectional view of a control piston and cylinderassembly together with a sectional view of the proportioning valveassembly.

FIG. 3 is a schematic view showing one embodiment of the two controlvalves utilized in the system.

In the drawings like characters of reference indicate correspondingparts in the different figures.

Proceeding therefore to describe my invention in detail, referenceshould be made first to FIG. 1 which shows schematically theincorporation of my invention in an hydraulic system.

Reference character 10 illustrates a work cylinder having a piston 11therein secured to a piston rod 12 which extends from one end 13 of thework cylinder. This portion of the apparatus is normally situated on theagricultural implement and the end 14 of the piston rod 12 is connectedto the implement component operated hydraulically as, for example, theblades of a cultivator.

For purposes of clarification, it is assumed that in this instance thepiston rod 12 is connected to an implement component so that when thepiston 11 moves in the direction of arrow 15, the implement is loweredor penetrates the soil and when the piston 11 is moved in a directionopposite to arrow 15, then the implement component is raised.

Also for clarification, the end 16 of the cylinder 10 is defined as thedown side of said cylinder and the aforementioned end 13 is consideredto be the up side of the cylinder.

A conduit 17 is connected to the cylinder 10 adjacent the end 13 thereofand extends, via conventional flexible hosing, to the tractor or sourceof power and is connected to a control box shown schematically in FIG. 3and collectively designated 18.

This control box includes-the fluid reservoir 19, a fluid pressure pump20, and a control valve assembly collectively designated 21. Thiscontrol valve is conventional in construction and is shown schematicallyin FIG. 3, it consists of a body portion 22 which is aperturedlongitudinally to receive a shuttle valve 23. This shuttle valve isprovided with relieved portions 24, 25 and 26 along the length thereof.A conduit from pump 20 leads into the body portion 22 and thence to theaxial bore therein at two locations, namely 20A and 20B. Conduit 17 isconnected through the body portion adjacent the relieved portion 24 andconduit 27 passes through the body portion and connected to the relievedportion 26.

Conduits 20C extend from the body poltion to the reservoir 19. With theshuttle valve in the position shown in FIG. 3, there is no connectionbetween conduits 20A and 20B from the pump to the valve as these areblanked off in this position by the body of the shuttle valve.

However, oil being circulated by the pump passes through the bypassconduit 20D, through the relieved portion 25 and thence is returned tothe reservoir '19.

The aforementioned conduit 27 extends to a control piston and cylinderassembly collectively designated 28, the conduit 27 entering thecylinder 29 of the assembly 28 adjacent the end thereof.

This conduit 27 extends operatively from adjacent the end 31 of thecylinder 29 to the end 16 of the work cylinder so that in eflect conduit27 consists of a first portion connected to end 30 of cylinder 29 and afurther portion extending between the end 31 of cylinder 29 and the end16 of cylinder 10, thereby placing cylinder 29 in series between thecontrol valve 21 and the work cylinder 10.

Reciprocal within cylinder 29 is a free moving piston 32, conventionalseals being provided therearound to prevent leakage of fluid therepast.

The aforementioned valve 21 is capable of three positions, firstly theneutral position shown in FIG. 3 and hereinbefore described.

The second position may be termed the down position occurs when theshuttle valve 23 is moved downwardly thus connecting conduit 17 toconduit 20B through the relieved portion 24. This downward movement alsoconnects conduit 27 to the reservoir conduit 20C through the relievedportion 26. In this position, fluid under pressure from pump 20 flowsthrough conduit 20B into relieved portion 24 and thence to conduit 17thus moving piston 11 within cylinder 10, in a direction of arrow 15.Fluid displaced by piston 11 travels via conduit 27 into cylinder 29 andmoves freely floating piston 32 also in the direction of arrow 15. Fluiddisplaced by the freely moving piston 32 travels along conduit 27,through relieved portion 26 and thence to the reservoir through 20C.This action lowers the implement component connected to the end 14 ofthe piston rod 12 and it will be observed that the lower action willcontinue until piston 11 abuts end 16 or until piston 32 abuts end 30 ofthe cylinder 29 at which time, of course, no further movement can takeplace.

If the shuttle valve 23 is in the up position, then conduit 20A,extending from the pump 20, connects to conduit 27 through relievedportion 26 and conduit 17, connects to reservoir conduit 20C, throughrelieved portion 24.

Under these circumstances, fluid under pressure flows through conduit27, thus moving piston 32 along cylinder 29 and displacing fluid throughthe further portion of conduit 27, into the end 16 of cylinder 10. Thismoves piston 11 in a direction opposite to arrow thus raising theimplement component connected to the end 14.

Fluid displaced by piston 11 travels along conduit 17 through relievedportion 24 and thence to the reservoir via C.

Arrows placed adjacent the conduits 17 and 27 are labelled up and downand refer to the movement of the implement component secured to pistonrod 12. It will be appreciated that the operation of the device ashereinbefore described is relatively conventional with the exceptionthat cylinder 29 is in series with conduit 27.

However, in order to adjust the end of the down stroke of piston 11, Iprovide a further conduit 35 extend ing from the portion of conduit 27connected to the end 31 of the cylinder 29. This conduit 35 is connectedto the aforementioned control box 18.

Within this box is a further control valve collectively designated 36.This is similar in construction to the control valve 21 and has beengiven prime numbers.

The shuttle valve 23' operates in the same manner as hereinbeforedescribed between the neutral position, the down position and the upposition.

For the purpose of illustration, the adjustment of the device is madewith the freely floating piston 32 abutting against end 30 of cylinder29 or in other Words, at the maximum down position.

At this point, shuttle valve 23' is returned to the neutral position bythe conventional spring (not illustrated) with the system locked andpump 20 merely circulating fluid through conduit 20D to the reservoir.

At this point control valve 23' is operated in either of the twopositions depending upon the position it is desired to preset piston 11.If we assume for the moment that piston 11 is also against end 16 of thecylinder 10, in other words, in the maximum down position and it isdesired to reset the down position and the up position.

For the purpose of illustration, the adjustment of the device is madewith the freely floating piston 32 abutting against the end 30 ofcylinder 29 or in other words, at the maximum down position.

At this point, shuttle valve 23 is returned to the neutral position bythe conventional spring (not illustrated) with the system locked andpump 20 merely circulating fluid through conduit 20D to the reservoir.

At this point control valve 23 is operated in either of the twopositions depending upon the position it is desired to preset piston 11.If we assume for the moment that piston 11 is also against end 16 of thecylinder 10, in other words, in the maximum down position and it isdesired to reset the down position to a lesser degree of penetrationthen the shuttle valve 23' is moved upwardly to connect pump conduit toconduit 35 and conduit 17 to reservoir via conduict 200.

When the valve 23 is in the above mentioned position, fluid underpressure from the pump 20 flows through relieved portion 26' and intoconduit 35. Inasmuch as piston 32 is deadended against end 30 and thesystem is locked in any event, fluid passes down conduit 35 and into theportion of conduit 27 connected to the end 16 of cylinder 10. This movespiston 11 in the direction opposite to arrow 15, any fluid beingdisplaced passing through conduit 17, and thence through relievedportion 24' to the reservoir. This raises the implement component andwhen it has been raised to the point where the depth penetration issutficient, valve 23' is moved back to the neutral position.

Valve 23 is then operated to move piston 32 towards end 31 of thecylinder thus moving piston 11 towards the end 13, of cylinder 10 thusraising the implement component. When the implement component is loweredby changing the position of valve 23, free floating piston 32 strikesthe end 30 of cylinder 29 at the same time that piston 11 reaches themaximum down position orginally preset. This piston 11 cannot travel anyfurther because the system is now locked so that the depth control iseffective.

It will also be appreciated, of course, that by changing the position ofvalve 23, the piston 11 can be moved in the direction of arrow 15 sothat piston 11 can be positioned anywhere within cylinder 10 and it willnot exceed these limits when operated by the action of piston 32.

The aforementioned embodiment presupposes cylinders 29 and 10 being ofsimilar volumetric capacity.

However, occasionally cylinder 10 is of relatively large capacity and itis not desirable to provide a similarly large cylinder 29.

Under these circumstances, I can utilize the embodiment shown in FIG. 2which incorporates a proportioning valve assembly collectivelydesignated 36A.

This proportioning valve assembly is provided so that the flow of fluidinto cylinder 29 may be limited. In other words the fluid flow isdivided by the proportioning device 36.

It consists of a body portion 37 which is hollow internally and theportion of the conduit 27 extending from the end 31 of cylinder 29, isconnected via nut 38, to one end 39 of this body portion.

A conduit 40 extends from end 30 of cylinder 29 to adjacent end 41 ofthe body portion 37.

The first portion of conduit 27 connected to the end 30 of the cylinder29, extends inwardly and is provided with a flared valve seat 42. Springloaded ball 43 is carried within one side 44 of piston 32 and whenpiston 32 reaches the end 30 of the cylinder, the ball engages the seat42 on the end of conduit 27 thus cutting ofl the flow. This relieves thepressure against the seals around the piston and also prevents shockloading occurring.

A cylindrical sleeve valve 45 extends within the end 41 of the bodyportion 37 of the proportioning valve, the inner end 46 of the sleevevalve being tapered and adapted to engage a tapered seat 47 situatedwithin the body portion 37 intermediate the ends thereof. This sleevevalve is screwthreadably secured within a gland nut 48 which in turn isscrewthreaded within the end 41. A disc 49 or the like is secured to theend of the sleeve valve so that it can be manipulated by the operator.

A stern valve 50 is screwthreadably engaged concentrically within thesleeve valve 45 and extends clear through. This terminates in a valvehead 51 reversed to valve end 46 and this valve head is engageablewithin a seating 52 within the body portion between valve seat 47 andend 39 thereof.

This valve 51 is reversed to valve 46. A passage or drilling 53 extendsfrom the body portion 37 between valves 47 and 52 and is connected via aconduit 54. to the end 16 of the work cylinder 10. This conduit 54 is infact a portion of the aforementioned conduit 27.

A drilling 55 extends between the body portion 37 and housing 54 betweenvalve 52 and the end 39 and a check valve in the form of ball 56, restsupon a seating 57 within this driling. A very light spring 56' maintainsthe ball on the seating 57.

Finally, a further drilling or conduit 58 extends be tween the bodyportion 37 and housing 54 and is situated between valve seating 47 andthe end 41 of the body portion and a ball valve 58' engages seating 58",a relatively heavy spring maintaining this ball upon the seat.

In operation, this particular embodiment is used when the work cylinderhas a greater displacement than the control cylinder 29. In thisembodiment and with the proportioning valve in use, the piston 32travels the full length of the cylinder 29 and the depth control ofpiston 11 is controlled by the rate at which piston 32 is permitted totravel towards the left-hand end 30.

The valve 49 controls the division of flow of fluid passing throughhousing 54 and it should be observed that valves 46 and 51, once theyare preset, work in opposition to one another. In other words, if valve46 is opened more, then valve 51 closes slightly. This proportions theflow of fluid passing through conduit 27 and conduit 40. The greaterquantity of fluid permitted to pass through conduit 27, the fasterpiston 32 will move towards end 30 and stop the piston 11 fromtravelling downwardly any further. It will therefore be seen that thedepth of the implement controlled by piston 11 is controlled by theopening and closing of the valve 49 which in turn controls the rate oftravel of piston 32.

As soon as ball valve 43 engages the valve seat 42, the system is lockedand the piston 11 cannot travel downwardly any further. When theimplement is raised, the

fluid flow is reversed as hereinbefore described and piston 32 movestowards the end 31 displacing fluid before it, through conduit 27. Thisfluid lifts the valve 56 which is held with a very light spring, andfluid flows through the drilling 55, through conduit '54 and intocylinder 10 thus moving piston 11 in the direction opposite to arrow 15and raising the implement. It should be noted that the spring loadedvalve 56 always unloads prior to the spring loaded valve 58'. Thisensures that piston 32 always engages end 31 of cylinder 29 and then ifpiston 11 has not reached the end of its stroke, fluid under pressurepasses through conduit 40 and through the heavier loaded spring valve 58thus ensuring that piston 11 completes its stroke.

Valves 46 and 51 are adjusted so that in order to provide restrictivecontrol which is essential so that positive pressure develops upon theright hand side of the piston 32 (with reference to 'FIG. 2) thisensures that this piston moves towards end 30 and provides aditferential in pressure upon either side of the piston, the fluidpassing through conduit 40, venting through conduit 27.

Once the relationship between valves 46 and 51 has been set by rotationof shaft 50, it is not normally necessary to reset these. The downposition of piston 11 is set by wheel or disc 49 which, of course,rotates over valve 46 and valve 51-.

However, during operation it is sometimes necessary to adjusttemporarily'the draft of the implement and in these circumstances, ofcourse, the control valve 23' is operated through conduit 35 thusbypassing the portioning valve assembly. Once this condition has passed,the control valve is returned to neutral and the relationship betweenpiston 11 and piston 32 is restored.

Finally it should be observed that ball valve 43 is desirable in bothembodiments in order to relieve hydraulic pressure from the sealssurrounding piston 32 and to prevent mechanical shock from occurring aspiston 32 reaches the end 30 of the cylinder 29.

With the ball valve 43 closing 01f conduit 27, where fluid underpressure passes through conduit 27, the ball valve is immediatelydisplaced against the spring pressure thus enabling the fluid pressureto operate against piston 32.

Although the foregoing deals with down" stroke control normally requiredwhen the device is used with agricultural equipment, nevertheless itwill be appreciated that the device can be used to control both down andup strokes depending upon the design parameters of the equipment beingcontrolled.

What is claimed to be the present invention is:

1. A variable stroke control device for use with a work piston andcylinder assembly, a fluid pump assembly, a control valve assembly, afirst conduit extending between said control valve assembly and the upside of said cylinder and a second conduit extending between saidcontrol valve assembly and the down side of said cylinder; said variablestroke control device being operatively connected in series with saidsecond conduit and including a control cylinder, and a free floatingpiston therein, said second conduit including a portion connecting withsaid control cylinder on one side of said free floating piston and afurther portion connecting with said control cylinder on the other sideof said free floating piston, said portion connecting to said controlvalve assembly, said further portion connecting to said down side ofsaid work cylinder, a work-piston-positioning valve assembly operativelyconnected between said pump and the down side of said cylinder bypassingsaid control cylinder, and means to actuate said work-piston-positioningvalve assembly.

2. In a hydraulic system including a source of fluid pressure, a workpiston and cylinder assembly, a control valve between said source offluid pressure and said work piston and cylinder assembly, a firstconduit extending from said control valve to the down side of said workpiston and cylinder assembly, and a second conduit extending betweensaid control valve and the up side of said work piston and cylinderassembly; means to preset the down position of said piston within saidcylinder and further means to prevent said piston from moving past saidpreset position on the down stroke of said piston, said second meanscomprising a control cylinder in series with said first conduit and afree floating piston in said control cylinder.

3. The device according to claim 2 in which said first means includes asecond control valve operatively connected to said source of fluidpressure, a bypass conduit extending between said second control valveand the said down side of said work cylinder.

4. The device according to claim 1 which includes a proportioning valveassembly operatively connected between said control piston and cylinderand the down side of said work cylinder for adjustably controlling thevolume of fluid passing into said control piston and cylinder.

5. The device according to claim 2 which includes a proportioning valveassembly operatively connected between said control piston and cylinderand the down side of said work cylinder for adjustably controlling thevolume of fluid passing into said control piston and cylinder.

6. The device according to claim 3 which includes a proportioning valveassembly operatively connected between said control piston and cylinderand the down side of said work cylinder for adjustably controlling thevolume of fluid passing into said control piston and cylinder.

7. The device according the claim 4 in which said proportioning valveassembly is connected to said further portion of said second conduit,said proportioning valve assembly including a body portion, anadjustable fluid flow dividing assembly in said body portion, said fluidflow dividing assembly including an adjustable sleeve valve, a seat forsaid valve, an adjustable stem valve con centrically mounted in saidsleeve valve, the seat for said stem valve, said sleeve valve and saidstem valve being 8 independently adjustable to control the division offluid flow in one direction through said valve, and check valves in saidproportioning valve to permit unrestricted fluid flow in the otherdirection through said valve.

8. The device according to claim 5 in which said proportioning valveassembly is connected to said further portion of said second conduit,said proportioning valve assembly including a body portion, anadjustable fluid flow dividing assembly in said body portion, said fluidflow dividing assembly including an adjustable sleeve valve, a seat forsaid valve, an adjustable stem valve concentrically mounted in saidsleeve valve, the seat for said stem valve, said sleeve valve and saidstem valve being independently adjustable to control the division offluid flow in one direction through said valve, and check valves in saidproportioning valve to permit unrestricted fluid flow in the otherdirection through said valve.

9. The device according to claim 6 in which said proportioning valveassembly is connected to said further portion of said second conduit,said proportioning valve assembly including a body portion, anadjustable fluid flow dividing assembly in said body portion, said fluidflow dividing assembly including an adjustable sleeve valve, a seat forsaid valve, an adjustable stem valve concentrically mounted in saidsleeve valve, the seat for said stern valve, said sleeve valve and saidstern valve being independently adjustable to control the division offluid flow in one diretcion through said valve, and check valves in saidproportioning valve to permit unrestricted fluid flow in the otherdirection through said valve.

References Cited UNITED STATES PATENTS 2,733,691 2/1956 Johnson 92133,111,062 11/1963 Peros 9213 PAUL E. MASLOUSKY, Primary Examiner U.S.Cl. X.R.

